doc/v628/rf903__numintcache_8py.html

import sys

import ROOT


def getWorkspace(mode):

    # Create, save or load workspace with pdf

    # -----------------------------------------------------------------------------------

    #

    # Mode = 0 : Create workspace for plain running (no integral caching)

    # Mode = 1 : Generate workspace with precalculated integral and store it on file

    # Mode = 2 : Load previously stored workspace from file


    w = ROOT.RooWorkspace()


    if mode != 2:

        # Create empty workspace workspace

        w = ROOT.RooWorkspace("w", 1)


        # Make a difficult to normalize  pdf in 3 dimensions that is

        # integrated numerically.

        w.factory(

            "EXPR::model('1/((x-a)*(x-a)+0.01)+1/((y-a)*(y-a)+0.01)+1/((z-a)*(z-a)+0.01)',x[-1,1],y[-1,1],z[-1,1],a[-5,5])"

        )


    if mode == 1:

        # Instruct model to precalculate normalization integral that integrate at least

        # two dimensions numerically. In self specific case the integral value for

        # all values of parameter 'a' are stored in a histogram and available for use

        # in subsequent fitting and plotting operations (interpolation is

        # applied)


        # w.pdf("model").setNormValueCaching(3)

        model = w["model"]

        model.setStringAttribute("CACHEPARMINT", "x:y:z")


        # Evaluate pdf once to trigger filling of cache

        normSet = {w["x"], w["y"], w["z"]}

        model.getVal(normSet)

        w.writeToFile("rf903_numintcache.root")


    if mode == 2:

        # Load preexisting workspace from file in mode==2

        f = ROOT.TFile("rf903_numintcache.root")

        w = f.Get("w")


    # Return created or loaded workspace

    return w


mode = 0

# Mode = 0 : Run plain fit (slow)

# Mode = 1 : Generate workspace with precalculated integral and store it on file (prepare for accelerated running)

# Mode = 2 : Run fit from previously stored workspace including cached

# integrals (fast, run in mode=1 first)


# Create, save or load workspace with pdf

# -----------------------------------------------------------------------------------


# Make/load workspace, here in mode 1

w = getWorkspace(mode)

if mode == 1:

    # Show workspace that was created

    w.Print()


    # Show plot of cached integral values

    hhcache = w.expensiveObjectCache().getObj(1)

    if hhcache:

        ROOT.TCanvas("rf903_numintcache", "rf903_numintcache", 600, 600)

        hhcache.createHistogram("a").Draw()

    else:

        ROOT.RooFit.Error("rf903_numintcache", "Cached histogram is not existing in workspace")

        sys.exit()


# Use pdf from workspace for generation and fitting

# -----------------------------------------------------------------------------------


# ROOT.This is always slow (need to find maximum function value

# empirically in 3D space)

model = w["model"]

d = model.generate({w["x"], w["y"], w["z"]}, 1000)


# ROOT.This is slow in mode 0, fast in mode 1

model.fitTo(d, Verbose=True, Timer=True, PrintLevel=-1)


# Projection on x (always slow as 2D integral over Y, at fitted value of a

# is not cached)

framex = w["x"].frame(Title="Projection of 3D model on X")

d.plotOn(framex)

model.plotOn(framex)


# Draw x projection on canvas

c = ROOT.TCanvas("rf903_numintcache", "rf903_numintcache", 600, 600)

framex.Draw()


c.SaveAs("rf903_numintcache.png")


# Make workspace available on command line after macro finishes

ROOT.gDirectory.Add(w)

Draw
th1 Draw()